As Loran Fades, Attention Shifts to DGPS and SBAS

November 30, 2009 - By

Few precise-positioning users have employed Loran in a professional sense, although maybe you have in your personal life if you’re a airplane pilot or a mariner. Then again, if you've flown as an airline passenger or cruised onboard a ship, you've benefited from the back-up to GPS that Loran provides. That back-up is about to go away. As attention and resources shift away from Loran, they focuses more intensely on GPS augmentations, specifically differential GPS (DGPS) and satellite-based augmentation systems (SBAS) such as WAAS and EGNOS. read more

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A Little Q&A Follow-up and Feedback on My Last Column

November 19, 2009 - By

I received some feedback on my last column entitled "What’s the Difference Between a Used Car Salesman and a GPS Salesman?" Most of the comments were positive in that the technical content was reasonably deep and thorough. However, I did receive a couple of e-mails from folks who were offended by the comparison. read more

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ABB Selects Intergraph for North African Gas Pipeline Project

November 4, 2009 - By

ABB has selected Intergraph for the development of an oil and gas pipeline network and relevant facilities in North Africa. The pipeline network will be built in the El Merk field, a remote, harsh desert location in Algeria. read more

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What’s the Difference between a Used Car Salesman and a GPS Salesman?

November 3, 2009 - By

I didn’t attend the Minnesota GIS/LIS Annual Conference last week, but I received a report from someone who attended a session in which the presenter seemed to fit the maxim quite well. One of the presenter’s messages was that people should stop using WAAS immediately as a GPS correction source due to the inability of data collection software to handle the ITRF00 > NAD83/CORS96 datum shift. Following is a statement from one of his slides… read more

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The System: Galileo Slips, EGNOS Operates

November 1, 2009 - By

Four Galileo in-orbit validation (IOV) satellites scheduled to launch next year have already missed their first pad date.The European version of Russia’s Soyuz rocket is now scheduled to carry the four IOV satellites into orbit in two launches in November 2010 and early 2011, as announced by European Space Agency (ESA) Director-General Jean-Jacques Dordain on October 9. Both launches had... read more

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On the Edge: Multipath Measures Snow Depth

November 1, 2009 - By

The September “Innovation” column in this magazine, “It’s Not All Bad: Understanding and Using GNSS Multipath,” by Andria Bilich and Kristine Larson (see, mentions the use of multipath in studying soil moisture, ocean altimetry and winds, and snow sensing. An experiment the authors conducted, designed to study soil moisture, yielded a surprise bonus: a new methodology for measuring snow depth via GPS multipath. It has important implications for weather and flood forecasting, and could also bring new insight to bear on GPS antenna design. read more

The True Story of the Origins of GPS

November 1, 2009 - By

Photos from the GPS World Leadership Dinner 2009, September 24 ION GNSS 2009 Conference, Savannah, Georgia read more

Expert Advice: GPS Constellation Maxed Out at 30

November 1, 2009 - By

It appears that the GPS satellite constellation has a glass ceiling, so to speak. GPS was designed as a 24-satellite constellation, with four satellites in six orbital planes arranged to provide maximum observability around the globe. According to the government’s Space-Based Positioning, Navigation, and Timing website, “The U.S. government is committed to provide a minimum of 24 operational GPS satellites on orbit, 95 percent of the time. The U.S. Air Force launches additional satellites that function as active spares to accommodate periodic satellite maintenance downtime and assure the availability of at least 24 operating satellites. As of August 28, 2009, there were 35 satellites in the GPS constellation, with 30 set ‘healthy’ to users.” read more

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